Variations of aminiums in fine particles at a suburban site in Guangzhou,China: Importance of anthropogenic and natural emissions

Amines are important nitrogen-containing compounds in fine particles (PM_2.5) in the atmosphere. Observations are necessary for in-depth understanding on the characteristics, sources and atmospheric processes of aminiums. In this study, the observation of ten C₁–C₄ aminiums in PM_2.5 was conducted in January and March of 2021 in suburban Guangzhou. The concentration and composition of aminiums showed significant differences between the pollution episodes and non-episode periods. Seasonal difference was also observed between winter and spring. The influence of meteorological factors (i.e., wind speed, atmospheric pressure, temperature and relative humidity) was investigated. The variations of aminiums were also affected by different sources. Anthropogenic sources were suggested to be major contributor to aminiums in the pollution episodes, while biological sources were important sources to aminiums in the non-episode periods, especially in spring. Positive matrix factorization receptor model was applied to investigate the source contributions, and four major sources were identified. The results show that vehicular emission, industrial production, biological emission and soil/dust were the major sources of aminiums. This study emphasizes the importance of source contribution and meteorological conditions on the variations of aminiums, which provides further understanding of organic nitrogen in the atmosphere.     

电感耦合等离子体原子发射光谱(ICP-AES)法测定四种奶片中的钙和镁

采用HNO3-HClO4混酸体系溶解奶片,电感耦合等离子体原子发射光谱法测定试样中的钙和镁含量,结果表明非糖果型奶片中钙和镁的含量较高。通过加标回收实验,钙和镁的加标回收率为96.7%～101%,相对标准偏差均小于3%,方法准确、快捷,为研究奶片在儿童成长发育中的作用提供了相关的依据。     

碘化钾-甲基异丁基甲酮萃取电感耦合等离子体发射光谱法测定磷酸一铵、磷酸二铵中铊含量

通过对观测方式、测定波长、共存元素干扰等因素进行分析和条件优化,建立了测定磷酸一铵、磷酸二铵中铊含量的碘化钾-甲基异丁基甲酮（KI-MIBK）萃取电感耦合等离子体发射光谱法。实验表明,直接采用电感耦合等离子体发射光谱法进行测定时,磷酸一铵、磷酸二铵中的锰元素对分析结果有正干扰。通过萃取分离,干扰被排除,测定结果准确、可靠。在0～1.0 mg/L范围内,铊的质量浓度与光谱强度呈良好的线性关系,相关系数达1.0000。该方法检出限为0.0072 mg/kg,相对标准偏差为4.28%（n = 10）,加标回收率在97.00%～100.5%之间。     

ICP-AES测定南红玛瑙中剧毒元素As、Cd、Cr、Pb、Sb含量的研究

文章研究报道了电感耦合等离子体发射光谱法测定南红玛瑙中As、Cd、Cr、Pb、Sb元素含量的分析方法。通过对前处理方法的确定、分析线的选择、基体干扰方面的研究,确定了分析条件,并对比研究了标准曲线法与标准加入法在测定方面的异同。标准加入法与标准曲线法的测定结果相近,但标准曲线法的测定结果总是比标准加入法的测定结果小。在标准加入法中,各元素加标回收率在93.6％～103％之间,测定值的相对标准偏差(RSD_n=6)小于10％;在标准曲线法中,各元素加标回收率在90.2％～103％之间,各元素的相对标准偏差(RSD _n=6)也均小于10％。基体效应对标准曲线法测定存在一定的影响,但不十分明显。标准加入法可以很好地减轻基体效应的干扰,但不可大批量测定样品。因此,在分析控制质量要求允许范围内,可采用标准曲线法对南红玛瑙中剧毒元素As、Cd、Cr、Pb、Sb的含量进行测定。     

开区注氮采空区自燃温度场的数值模拟研究

为了研究开区注氮采空区遗煤自燃和被抑制的力学过程,用非均质多孔介质中的渗流连续性方程、气体弥散方程和综合传热方程的联立,建立了采空区注氮非定常数值模型．结合实例,用迎风格式有限元方法求解．给出了采空区的漏风流态、氮气流态,描绘了采空区自燃过程中氧、CO浓度和温度分布的变化过程．计算考虑了瓦斯涌出和工作面推进的影响．得到注氮条件下采空区高温区形状变窄;随着注氮量的提高,使自然发火期逐渐变长,直至不自燃．理论计算与实际情况吻合．     

交流电弧发射光谱法测定地球化学样品中的高含量锡

建立了交流电弧发射光谱法测定化学样品中锡的方法。以氧化锌、氟化钠、硫粉为缓冲剂,改善元素蒸发行为;以锗为内标,样品与缓冲剂比例为1∶1。根据不同含量的锡选择不同级别灵敏线进行分析,采取内标法,建立浓度与相对强度之间的线性关系,计算出样品中锡的含量。实验中可以将锡的分析上限提高到x%,同时避免由稀释样品带来的分析误差。方法相对标准偏差(RSD,n=12)小于7%,测定了国家一级地球化学标准物质,结果与标准值相符。     

电感耦合等离子体原子发射光谱法(ICP-AES)测定铜砷滤饼中的Pb、Fe、Bi三种元素

采用硝酸、盐酸、氢氟酸、高氯酸分解样品,氢溴酸-盐酸挥发消除砷基体,优化仪器测定参数,选取最佳工作条件,建立了电感耦合等离子体原子发射光谱(ICP-AES)法测定铜砷滤饼中Pb、Fe、Bi元素的分析方法。其测定范围为：ω(Pb):0.12%~2.09%;ω(Fe):0.081%~2.10%;ω(Bi):1.20%~6.14%。各元素检出限为Pb:0.010μg/mL;Bi:0.006μg/mL;Fe:0.003μg/mL。加标回收率为95.5%~101.7%。该方法简便,准确,可靠,适用于铜砷滤饼中Pb、Fe、Bi元素的同时测定。     

原子吸收光谱和原子发射光谱法测定酸雨中钾、钠、钙、镁方法比较

采用原子吸收光谱法和原子发射光谱法分别测定了酸雨中的钾、钠、钙、镁4种元素的含量,并对两种方法的样品前处理技术、标准曲线、方法检出限、准确度、精密度、干扰及消除等进行了比较研究。结果表明,两种方法无显著性差异,均可用于酸雨中钾、钠、钙、镁4种元素的测定。     

Atomic emission of anhydrous hydrogen bromide: Spectra from 200 to 900 nm by sealed inductively coupled plasma-atomic emission spectroscopy

Anhydrous hydrogen bromide, at concentrations of up to 25%, has been introduced into a sealed inductively coupled plasma system for spectrochemical analysis. The emission spectra of 15% anhydrous hydrogen bromide is reported over the spectral range of 200 to 900 nm from an enclosed inductively coupled plasma discharge operated at atmospheric pressure and 1.1 kW. More than 140 atomic Br I lines are identified and reported along with their relative intensities. Where possible, molecular band assignments of Br₂ are made. Impurities identified qualitatively include Fe, Sn, C, and Ni. The presence of these impurities were verified by gas phase hydrolysis and subsequent inductively coupled plasma-mass spectrometry analysis.     

Direct and Indirect Chemiluminescence: Reactions,Mechanisms and Challenges

Emission of light by matter can occur through a variety of mechanisms. When it results from an electronically excited state of a species produced by a chemical reaction, it is called chemiluminescence (CL). The phenomenon can take place both in natural and artificial chemical systems and it has been utilized in a variety of applications. In this review, we aim to revisit some of the latest CL applications based on direct and indirect production modes. The characteristics of the chemical reactions and the underpinning CL mechanisms are thoroughly discussed in view of studies from the very recent bibliography. Different methodologies aiming at higher CL efficiencies are summarized and presented in detail, including CL type and scaffolds used in each study. The CL role in the development of efficient therapeutic platforms is also discussed in relation to the Reactive Oxygen Species (ROS) and singlet oxygen (¹O₂) produced, as final products. Moreover, recent research results from our team are included regarding the behavior of commonly used photosensitizers upon chemical activation under CL conditions. The CL prospects in imaging, biomimetic organic and radical chemistry, and therapeutics are critically presented in respect to the persisting challenges and limitations of the existing strategies to date.